It’s nice to find bits and pieces that add to a collection – some time ago I found a small shop display for the Cosmotron models. Dating from the early 1970s, it holds three watches – here’s a little ‘fly by’:

http://s282.photobucket.com/user/Sweephand/media/Cosmotron%205800/CosmoTrioVid.mp4.html?sort=3&o=1

Although the three models on the stand share the same dial design, the one in the centre has the 0840 movement, which runs at 21,600 beats per hour and dates from 1972. It also carries the X8 logo: https://sweep-hand.org/2012/09/18/this-weeks-featured-watch-40-the-cosmotron-x8-0840/. The other two are slightly later models, now without the X8 mark, and run at twice the speed – 43,200 beats per hour. This is the 5800 movement, Citizen’s fastest beating vintage watch with a conventional balance assembly. These two date from 1974 and 1975: https://sweep-hand.org/2011/09/21/this-weeks-featured-watch-14-the-cosmotron-5800/